{"product_id":"cylinder-with-piston-o-54mm-ms660-066","title":"Cylinder with Piston Ø 54mm MS660, 066","description":"\u003ch1\u003eSTIHL Cylinder with Piston 54mm for 066 and MS660 - Genuine OEM - 1122 020 1209\u003c\/h1\u003e\n\u003cp\u003eThe \u003cstrong\u003eSTIHL Cylinder with Piston 54mm\u003c\/strong\u003e (part number \u003cstrong\u003e1122 020 1209\u003c\/strong\u003e) is a genuine OEM top-end assembly for the STIHL \u003cstrong\u003e066\u003c\/strong\u003e and \u003cstrong\u003eMS660\u003c\/strong\u003e chainsaws, supplied as a complete kit including the \u003cstrong\u003e54mm chrome-lined cylinder\u003c\/strong\u003e, matched piston, two piston rings, gudgeon pin, circlips and decompression valve. Restores compression, power delivery and starting reliability on a worn or damaged top end, returning the engine to original specification. Available from Gustharts, an authorised STIHL dealer with UK stock ready to ship.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e⚠ This part fits 066 and MS660 chainsaws manufactured before July 2003 only.\u003c\/strong\u003e Machines produced from July 2003 onwards require part number \u003cstrong\u003e1122 020 1211\u003c\/strong\u003e, which is a separate component. Always confirm your machine's serial number and production date before ordering. Contact Gustharts with your serial number if you need confirmation.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eNote: 1122 020 1209 and 1122 020 1211 are not interchangeable.\u003c\/strong\u003e They are different parts for different production runs of the same model — not alternate formats of the same number.\u003c\/p\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eGenuine STIHL OEM top-end assembly\u003c\/strong\u003e — manufactured to original specification for correct bore geometry, compression ratio and thermal management\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart number 1122 020 1209\u003c\/strong\u003e — also referenced as 1122-020-1209 and 11220201209; fits 066 and MS660 before July 2003 only\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e54mm chrome-plated bore cylinder\u003c\/strong\u003e — original-specification chrome lining for durability, low friction and heat dissipation in sustained heavy-duty cutting\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eComplete kit\u003c\/strong\u003e — cylinder, piston, two piston rings, gudgeon pin, circlips and decompression valve supplied as a matched assembly\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRestores compression and power\u003c\/strong\u003e — returns worn, scored or seized engines to original displacement and compression specification\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMatched piston and bore\u003c\/strong\u003e — factory-clearanced piston-to-bore fit prevents premature ring and bore wear during run-in\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDecompression valve included\u003c\/strong\u003e — the MS660's decompression system reduces starting effort; supplied as part of this assembly\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrecision machined mating surfaces\u003c\/strong\u003e — correct head gasket seating and port alignment for proper gas flow and combustion\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eTechnical Specification\u003c\/h2\u003e\n\u003cdiv style=\"overflow-x: auto;\"\u003e\n\u003ctable style=\"width: 100%; border-collapse: collapse; text-align: left; border: 1px solid #ddd;\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003eBrand\u003c\/th\u003e\n\u003ctd style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003eSTIHL\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003eProduct Type\u003c\/th\u003e\n\u003ctd style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003eCylinder with Piston Assembly (top-end kit)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003eManufacturer Part Number\u003c\/th\u003e\n\u003ctd style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003e1122 020 1209\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003eAlternate Part Number Formats\u003c\/th\u003e\n\u003ctd style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003e1122-020-1209, 11220201209\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003eBore Diameter\u003c\/th\u003e\n\u003ctd style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003e54mm (2.13\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003eCylinder Bore Type\u003c\/th\u003e\n\u003ctd style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003eChrome-plated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003eKit Contents\u003c\/th\u003e\n\u003ctd style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003eCylinder, piston, 2x piston rings, gudgeon pin, circlips, decompression valve\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003eCompatible Models\u003c\/th\u003e\n\u003ctd style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003eSTIHL 066 and MS660 manufactured before July 2003 only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003ePost-July 2003 Part\u003c\/th\u003e\n\u003ctd style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003e1122 020 1211 (separate part — not a format variant of 1209)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003ePart Type\u003c\/th\u003e\n\u003ctd style=\"border: 1px solid #ddd; padding: 10px; text-align: left;\"\u003eGenuine OEM Replacement Part\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003ch2\u003eWhy Choose a Genuine STIHL Cylinder Assembly?\u003c\/h2\u003e\n\u003cp\u003eThe MS660 is STIHL's largest-displacement production chainsaw at 91.6cc — a 5.2kW professional tool used in demanding timber processing, large-section felling and heavy arborist work where sustained full-load running is the norm rather than the exception. At this power level, the cylinder and piston assembly operates under significant thermal and mechanical stress. Bore geometry, chrome layer thickness, piston ring end-gap and piston-to-bore clearance are all tightly toleranced at the factory specifically for these conditions.\u003c\/p\u003e\n\u003cp\u003eAftermarket top-end kits are widely available for the MS660 at significantly lower cost. Many use Nikasil-lined bores rather than the chrome plating of the original, which has different run-in requirements and can behave differently under the thermal cycling typical of professional forestry use. Chrome-lined cylinders are generally more tolerant of contaminated fuel and abrasive airborne particles — relevant considerations for an MS660 running in dusty site conditions. The OEM piston-to-bore clearance is factory-set and tested; aftermarket kits vary in whether this clearance is correctly matched to the chrome bore specification. For a component where a seizure means engine destruction on a saw of this value, the cost difference between genuine and aftermarket rarely justifies the risk.\u003c\/p\u003e\n\u003ch2\u003eAlso Known As\u003c\/h2\u003e\n\u003cp\u003eThe STIHL cylinder with piston assembly is also referred to as a \u003cstrong\u003etop-end rebuild kit\u003c\/strong\u003e, pot and piston kit, barrel and piston assembly, jug and piston set, cylinder head and piston assembly, and engine top-end kit. For the MS660 and 066 specifically, it is commonly searched as a \u003cstrong\u003eMS660 cylinder kit\u003c\/strong\u003e, \u003cstrong\u003e066 top-end kit\u003c\/strong\u003e or \u003cstrong\u003eMS660 bore kit\u003c\/strong\u003e. For correct ordering, always use STIHL part number \u003cstrong\u003e1122 020 1209\u003c\/strong\u003e for pre-July 2003 machines, or \u003cstrong\u003e1122 020 1211\u003c\/strong\u003e for July 2003 onwards, and confirm your production date before purchasing.\u003c\/p\u003e\n\u003ch2\u003eOften Replaced Alongside\u003c\/h2\u003e\n\u003cp\u003eA top-end rebuild on the MS660 is a natural point to inspect and replace related components that share the same service interval or are disturbed during cylinder removal:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003ca href=\"\/collections\/stihl-spare-parts\"\u003eHead gasket and cylinder gasket set for MS650\/MS660 (1122 007 1053)\u003c\/a\u003e — always fit new gaskets when replacing the cylinder; do not reuse old gaskets\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/collections\/stihl-spare-parts\"\u003eDecompression valve for MS660 (1128 020 9400)\u003c\/a\u003e — inspect when the cylinder is removed; replace if the valve seat shows wear\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/collections\/stihl-spare-parts\"\u003eSpark plug (NGK BPMR7A)\u003c\/a\u003e — replace at every top-end rebuild as standard service practice\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/collections\/sharpening-maintenance-tools\"\u003eSTIHL chain oil and 2-stroke oil\u003c\/a\u003e — correct run-in lubrication is essential when commissioning a new cylinder assembly\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eExplore More\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/collections\/stihl-spare-parts\"\u003eSTIHL Spare Parts\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/pages\/stihl-parts\"\u003eSTIHL Parts Finder\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/pages\/stihl-machinery\"\u003eSTIHL Machinery\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eFAQs\u003c\/h2\u003e\n\u003ch3\u003eWhich machines does part 1122 020 1209 fit?\u003c\/h3\u003e\n\u003cp\u003eThis part fits STIHL 066 and MS660 chainsaws manufactured before July 2003 only. Machines from July 2003 onwards require part 1122 020 1211, which is a separate component — not an alternate format of this part number.\u003c\/p\u003e\n\u003ch3\u003eWhat is included in the kit?\u003c\/h3\u003e\n\u003cp\u003eThe kit includes: 54mm chrome-plated cylinder, matched piston, two piston rings, gudgeon pin, circlips and decompression valve — everything required for a complete top-end rebuild.\u003c\/p\u003e\n\u003ch3\u003eWhat is the bore diameter of this cylinder?\u003c\/h3\u003e\n\u003cp\u003e54mm (approximately 2.13\"), matching the original factory specification of the STIHL MS660 and 066 engine at 91.6cc displacement.\u003c\/p\u003e\n\u003ch3\u003eIs this a chrome or Nikasil cylinder?\u003c\/h3\u003e\n\u003cp\u003eThis is a genuine STIHL OEM part with a chrome-plated bore — the original factory specification for the MS660\/066. Aftermarket alternatives sometimes use Nikasil liners, which have different run-in requirements and characteristics. Always follow the run-in procedure specified in the STIHL service manual when fitting a new cylinder.\u003c\/p\u003e\n\u003ch3\u003eHow do I confirm my machine's production date?\u003c\/h3\u003e\n\u003cp\u003eThe production date is encoded in your machine's serial number. Check the data plate on the machine or contact Gustharts with your serial number and we will confirm which cylinder assembly is correct for your saw.\u003c\/p\u003e","brand":"Stihl","offers":[{"title":"Default Title","offer_id":58123755323766,"sku":"ST-1122 020 1209","price":247.92,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0690\/6603\/1348\/files\/STIHL_genuine_spares_from_authorised_dealer.png?v=1775040092","url":"https:\/\/www.gustharts.com\/products\/cylinder-with-piston-o-54mm-ms660-066","provider":"Gustharts","version":"1.0","type":"link"}